completeness: While repetitive or unnecessary information must be eliminated, the writer has a responsibility to provide essential information on a given topic. For example, in a definition of chicken pox, the leader would expect to learn that it is primarily a children's disease characterized by a rash. he would also expect to learn that it is also referred to as "varicella." Failure to provide essential information is indeed an error. Just because a source you have chosen does not include certain information, you are not excused from supplying all the basics in your essay. For this reason as well as others, you must consult a variety of sources.